Hi Divya,
ISCA is a simple book. But the nightmare is it is similar in most of chapters.
Concentrate more on second half (10, 9 8 7 6 Chapters)
1. They are not identical to each other.
2. Terminology is different. hence u can memorise easily. Just read once and take institute material - sub headings only as notes to remember. Because in exams they can recognize only when its written from study material. They are some questions like, Threats, significance, characteristics, features.. as common for all chapters. try to find the difference between them, so that u can recognize from which chapter it is asked. Questions seems similar to all. But answers given in study material is different.
3. Dont spend more time in Chapter 3 and 9. these chapters are dry and u can try some thing relevant in exams for questions from these chapters of your own. Just read once. and Quick review b4 exam is enough
4. Chapters 1 and 2 u refer scanner questions. Most of the questions are repetative only.
5. Dont try to memorise all the chapters before exam day. u may confuse it. Avoid those chapter which u feel complicated. cover 6 to 8 chapters fully. u will surely score 60 plus.
6. Read happily, b'coz it makes u read more. Leave the habit of worrying. it makes to feel dry all the day.
:-)